This invention relates to antenna feed networks and, in particular, feed networks for satellite antennas.
Currently such feed networks include phase shifters and trombones to provide the required phase relationships. The phase shifters are of two types, namely inductive and capacitive, to ensure not only correct phase at midband but also to achieve equal phase slope among the many runs leading to the antenna horns. Many phase shifters are used in a typical communication satellite; for example, the G-STAR antenna has over a hundred phase shifters.
The cost of the phase shifter represents a major component in the overall cost of the feed network and the space occupied by the phase shifters significantly increases the size of the feed network.